|Publication number||US6537223 B1|
|Application number||US 09/654,921|
|Publication date||Mar 25, 2003|
|Filing date||Sep 5, 2000|
|Priority date||Sep 5, 2000|
|Also published as||WO2002019913A1, WO2002019913B1|
|Publication number||09654921, 654921, US 6537223 B1, US 6537223B1, US-B1-6537223, US6537223 B1, US6537223B1|
|Original Assignee||Medi-Stim As|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Non-Patent Citations (18), Referenced by (9), Classifications (11), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
This invention relates to the field of probes. More specifically, the invention relates to an ultrasonic probe head for measuring volume flow in vessels, particularly blood flow in arteries and veins, and the use of such probe head during conventional and endoscopic surgery.
2. Description of Related Art
Ultrasound probes are used in several applications, one application being the measurement of volume flow in vessels in connection with surgery. Prior art probe heads for measuring volume flow in vessels (e.g. veins and arteries) are generally based on the fact that the time required for ultrasound to pass through the vessel fluid is slightly longer when the ultrasound is transmitted against the fluid flow, than when it is transmitted in the same direction as the flow. In order to generate such transmission and record the difference in transit time, prior art probe heads for measuring volume flow in vessels in general and in principle comprise two crystals for transmitting and receiving ultrasound waves, and a passive device for reflecting same. The crystals are disposed on the one side of the vessel, at equal but opposite angles with respect to a plane perpendicular to the vessel longitudinal axis. The reflecting device is disposed on the other side of the vessel, diametrically opposite the crystals. The crystals and the reflector are arranged such that ultrasound waves reciprocally travel from one crystal, through the vessel, being reflected off the reflector, and returning through the vessel to be received by the other crystal. In order to having the ultrasound waves travelling in an as homogenous medium as possible, the gaps between the vessel and the crystals and between the vessel and the reflector, are filled with an acoustic transmitting fluid, such as e.g. blood or water or—if the vessel is not otherwise immersed—an acoustic coupling gel.
In order to keep the vessel in a fixed and stationary position between the crystals and the reflector during measurement, prior art probe heads are equipped with a sliding device, which is opened to receive or release the vessel and closed to retain the vessel.
It is in e.g. surgical procedures, essential that the vessel remains in a stationary and fixed position within the probe head. It is also important that the gel is kept in place between the vessel and the probe head in order to ensure reliable measurement.
One problem with known probe heads is that the gel is not well contained, and that flow measurements over extended periods of time thus are compromised due to the influence of air or other fluids having different acoustic properties.
Known probe heads are also cumbersome to operate, in that they require the actuation of movable sliding devices in order to place the exposed artery or vein in the probe head. This can at best be difficult to accomplish, given the environment in which the probe heads are being used, and the small size of the probe heads.
Conventional probe heads must also to some extent be disassembled for cleaning and sterilisation after use. This is time consuming and exposed the probe heads for excessive wear.
It is therefore a long felt need for a probe head intended for volume flow measurement in vessels, that is easy to manufacture, operate and clean, and that retains the gel for an extended period in order to maintain sufficient acoustic coupling.
The present invention solves that need, in that the probe head according to the invention contains few parts that are easily manufactured by conventional techniques and, when assembled, comprises one sealed unit with no movable parts. The invented probe head is thus easy to clean and sterilise, requiring no disassembly and reassembly. Furthermore, the vessel may easily be placed in the invented probe head, only by the user slightly twisting the probe head. The probe head in accordance with the invention also comprises a channel which in an improved manner retains the gel for an extended period, thereby ensuring sufficient acoustic coupling.
These and other objects and features of the invention are provided by an ultrasound probe head for measuring volume flow in vessels. In broad terms, the probe head comprises a housing, a support element, reflector-, crystal- and circuit means, and associated wires and cable.
The ultrasound reflector, piezo-electric crystals and circuit board are mounted onto respective dedicated surfaces in the support element, in an arrangement generally known in the art and electrically connected through wires to a measurement apparatus.
Inclined surfaces to which the crystals are mounted, are disposed in the upper region of the support element, symmetrically about a support element vertical axis. The support element is furthermore equipped with a bore for passing the electrical cable and a slit and a wire compartment for housing the electrical wires.
The ultrasound reflector is attached to the support element by fastening means, while the crystals and circuit board are affixed to the support element by means of a resilient compound. The support element, with the above mentioned parts assembled to it, is sealably coated with a resilient compound.
The probe head housing is made of a resilient material and comprises a compartment into which the support element is placed, a cable bore for the electrical cable bundle containing the wires to the crystals and circuit board, a recess into which a portion of the reflector is passed, spill guards for limiting acoustic coupling gel spillage, and vessel retainer flaps for retaining the vessel in a stationary position in the probe head while measurements are being performed.
The assembled probe head housing and support element are further sealed to constitute one sealed probe head unit, by the application of a resilient compound in the upper region of the housing.
The resilient compound filled in the upper region of the housing, above the affixed crystals and circuit board, forms together with the vessel retainer flaps, part of the reflector and the gel spill guards, a channel with generally planar surfaces, capable of receiving, supporting and retaining the vessel and an acoustic coupling gel.
The resilient vessel retainer flaps are flexible in order to letting the vessel be slipped into the channel. The flaps secure the vessel in a stationary position in said channel, and are sufficiently flexible for allowing a selective release of the vessel from the channel.
The assembled probe head may be used in connection with conventional surgery, where arteries and veins are exposed, and may be fitted to any known probe type. The assembled probe head may also be used in endoscopic procedures and may be fitted to any known endoscopic probe type.
The gel spill guards upper region or edge may have either an arcuate (concave or convex) horizontal or inclined shape.
The probe head housing upper lateral edges are formed as inwardly directed flanges adapted to catch the support element upper region.
FIG. 1 shows a probe head housing according to an embodiment of the present invention, in side view (FIG. 1a), front view (FIG. 1b) and top view (FIG. 1c).
FIG. 2 shows an ultrasound reflector according to an embodiment of the present invention, in bottom view (FIG. 2a), side view (FIG. 2b) and front view (FIG. 2c).
FIG. 3 shows a perspective rear view of a support element according to an embodiment of the present invention.
FIG. 4 shows a perspective rear view of a support element and, partly cut-away, a probe head housing, according to an embodiment of the present invention.
FIG. 5 shows a perspective exploded front view of a probe head according to an embodiment of the present invention.
FIG. 6 shows a perspective front view of an assembled probe head according to an embodiment of the present invention.
Referring to FIGS. 1-6, the preferred embodiment of the ultrasound probe head of the present invention comprises a probe head housing (10), support element (30) and an ultrasound reflector, circuit board (24) and piezo-electric crystals (23).
The ultrasound reflector (20) is attached to the support element (30) by means of a fastening device, for instance a bolt or pin (27) through respective holes (22, 32).
The piezo-electric crystals (23) are electrically connected by wires (25) to a circuit board (24), all being electrically connected to a measurement apparatus (26) through an electrical cable (21).
The support element (30), supports the piezo-electric crystals (23) on respective inclined crystal supporting surfaces (31), disposed on its upper region thereof and symmetrically about a support element vertical axis, and to which said crystals (23) are affixed. The circuit board (24) is disposed in the space between the crystals. Referring to FIG. 3, the support element also comprises a bore (33) through which the electrical cable (21) is passed, a slit (34) and a compartment (35) for housing the electrical wires (25).
Referring to FIG. 1, the probe head housing (10) has a compartment (15) for receiving the support element (30), a cable bore (13) through which the electrical cable (21) from the support element is passed, and a recess (14) for receiving a portion of the reflector (20). In addition, referring to FIGS. 1, 5 and 6, the housing also comprises gel spill guards (11) for limiting spillage of acoustic coupling gel, and resilient vessel retainer flaps (12) for selectively admitting, retaining and releasing the vessel in a stationary position in the probe head. Referring to FIG. 4, The probe head housing upper lateral edges are formed as inwardly directed flanges (17) adapted to catch the support element upper region.
The probe head housing is made of a resilient material, preferably silicone, but may be selected from a group comprising silicone, plastics, rubbers, etc.
The reflector (20), said ultrasound crystals (23), and said circuit board (24) are fixedly attached to said support element (30) in a fashion generally known in the art, and the assembly thereof is sealably coated with a resilient compound, preferably silicone.
The assembly comprising the probe head housing (10) and the assembled support element are further sealed to constitute one sealed probe head unit, by the application of a resilient compound, preferably silicone, in the upper region of the housing. This, in combination with the vessel retainer flaps (12), reflector (20) and gel spill guards (11), forms a vessel supporting channel (16) with generally planar surfaces which is capable of receiving and retaining on its surfaces an acoustic coupling gel. The above mentioned resilient compound in the preferred embodiment of the present invention is silicone, but may be selected from a group comprising silicone, plastics, rubbers, etc.
The resilient vessel retainer flaps (12) are capable of selectively being flexed in order to letting the vessel be slipped into the channel (16), and to selectively releasably securing the vessel in a stationary position in said channel in order to allow flow measurement, and selectively being flexed in order to releasing the vessel from the channel (16).
The assembled probe head in accordance with the preferred embodiment of the present invention may be used for measuring volume flow in blood vessels, either during conventional surgery where the blood vessels are exposed, or in endoscopic procedures where the vessels are accessed through holes in the thorax.
When using the probe head, the user first coats the probe head in acoustic coupling gel, which then is contained within the channel (16). The user then slips the vessel into the channel containing gel, by slightly flexing the retainer flaps (12) and/or the vessel. The vessel is retained in contact with the gel inside the channel for the desired duration, after which the reverse operation is performed to release the vessel from the channel.
The foregoing description and the embodiments of the present invention are to be construed as mere illustrations of the application of the principles of the invention. The foregoing is not intended to limit the scope of the claims, but the true spirit and scope of present invention is defined by the claims.
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|US7194919 *||May 29, 2003||Mar 27, 2007||Transonic Systems, Inc.||Acoustically coupled ultrasonic transit time flow sensors|
|US7469598 *||Mar 26, 2007||Dec 30, 2008||Transonic Systems, Inc.||Method of employing a transit time ultrasound sensor|
|US9226673||Mar 15, 2013||Jan 5, 2016||East Carolina University||Methods, systems and computer program products for non-invasive determination of blood flow distribution using speckle imaging techniques and hemodynamic modeling|
|US9271658||Jan 9, 2012||Mar 1, 2016||East Carolina University||Methods, systems and computer program products for non-invasive determination of blood flow distribution using speckle imaging techniques and hemodynamic modeling|
|US20040254469 *||May 29, 2003||Dec 16, 2004||Transonic Systems, Inc.||Acoustically coupled ultrasonic transit time flow sensors|
|US20050038343 *||Jul 9, 2004||Feb 17, 2005||Alfred E. Mann Institute For Biomedical Research At The University Of Southern California||Apparatus and method for locating a bifurcation in an artery|
|US20070186681 *||Mar 26, 2007||Aug 16, 2007||Transonic Systems, Inc.||Acoustically coupled ultrasonic transit time flow sensors|
|US20080129295 *||Mar 3, 2006||Jun 5, 2008||Koninklijke Philips Electronics N.V.||Seamless Enclosures for Mr Rf Coils|
|US20080236297 *||Jan 22, 2008||Oct 2, 2008||Geoff Van Fleet||Acoustically compatible insert for an ultrasonic probe|
|U.S. Classification||600/459, 600/468|
|International Classification||A61B8/00, A61B8/06, G01F1/66|
|Cooperative Classification||A61B8/4281, A61B8/4455, A61B8/06, G01F1/662|
|European Classification||A61B8/42F2, G01F1/66B|
|Sep 5, 2000||AS||Assignment|
Owner name: MEDI-STIM AS, NORWAY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KRISTIANSEN, KNUT;REEL/FRAME:011086/0969
Effective date: 20000830
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